The present invention relates essentially to a method of producing an extrusion tool operating as an extrusion die for non metallic material.
Many types of dies suitable for the extrusion of sectional rods, notably of plastic material, are known; their cost is generally high owing to the required machining precision. High cost is particularly burdensome in the case of research and development laboratories, which often require to test a large number of tools in order to specify the final production tools.
U.S. Pat. No. 3,825,456 discloses a tool made of a stack of glass plates in which apertures are formed through photoetching. Due to poor surface quality of the channels resulting from the stacking of the apertures a capillary glass lining is necessary to provide the smoothness necessary for extrusion. This kind of tool is much too expensive to be usable at the developmental stage.
It is an object of the present invention to provide particularly low price extrusion tools by means of which it is possible to obtain wires or rods of very great variety and complexity of sections.